1 Corinthians 14:10

Modern English Version

There are, it may be, so many kinds of languages in the world, and none of them is without significance.

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Therefore, if I do not know the meaning of the speech, I shall be a barbarian to him who speaks, and he who speaks will be a barbarian to me.

So also you, unless with the tongue you speak words easy to understand, how will it be known what is spoken? For you shall speak into the air.